A pod is a box you fold a thicket of organisms into. Its inside is a canvas of its own, so a colony that has grown dense keeps working exactly as it did while the patch above it gets its room back.
Getting signal in and out
A pod's box talks to the patch around it through two organisms. PodIn is the way in: everything you cord into the box from outside flows through a PodIn and appears on its outlet inside. PodOut is the way out: whatever you cord into a PodOut inside appears on the box's matching outlet pin outside. One organism per pin, in the order they were made.
Growing more pins
Add ports from the pod canvas's right-click menu, and the box grows matching pins. A port's editor re-classes it in place between Mono, Stereo and MIDI while keeping its name, so every cord already attached to it survives the change.